The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties therefor.
The invention relates in general to armor for protection from a projectile, and, in particular to armor that includes an explosive device.
There are various types of armor and armor systems used for protecting equipment from metal fragments, bullets and projectiles. Conventional armor is thick steel plate that is designed and manufactured for hardness and strength. Improvements in projectile technology have been responded to in armor technology by increasing the thickness of armor plate. However, there are practical limits to the thickness of any armor because of the weight that can be carried by military vehicles such as tanks, armored personnel carriers and like armored vehicles and still be militarily effective.
Reactive armor has been developed to overcome the weight limitations of armor plate. Reactive armor, and closely related concepts known as active armor, active protection, energetic armor, and smart armor, includes a layer or layers of explosive material positioned under an external layer or layers of armor. Any projectile penetrating the external layer of armor sets off the explosive material, resulting in a detonation that defeats the projectile.
U.S. Pat. No. 4,989,493 to E. J. Blommer et al. discloses a laminated structure for attenuating explosive shock waves. The structure includes layers of aluminum, plastic and rigid foam. The laminated structure is used to attenuate the explosive force of an accidental explosion thereby preventing sympathetic detonation of adjacent equipment.
U.S. Pat. No. 5,811,712 to M. Held discloses reactive armor. The reactive armor includes an explosive layer, a retardation layer, a flexibly displaceable front layer and an immovable rear wall layer.
U.S. Pat. No. 5,070,764 to H. Shevach discloses reactive armor. The reactive armor includes an explosive layer sandwiched between a first set of two metal plates and at least one passive mass and energy consuming assembly comprising a layer of non-explosive swellable material sandwiched between a second set of two metal plates. The swellable material is caused to swell to urge the two metal plates of the passive assembly to move apart. This action produces a mass and energy consumption to attenuate and mitigate the impact of armor piercing kinetic energy projectiles.
U.S. Pat. No. 4,981,067 to C. N. Kingery discloses reactive armor. The armor comprises a series of non-overlapping armor plates. Sandwiched between the armor plate is an explosive layer. The plates include a plurality of small holes that reduce the mass of the reactive armor.
A reactive armor in accordance with the invention includes an orderly stack of multiple leaves of solid explosive material, interleaved with solid, compressible foam. An armor plate provides means for compressing the stack. The armor plate is moveable between a first position in which the stack is compressed and a second position in which the stack is uncompressed. An igniter is in communication with the leaves of explosive.
Each of the multiple leaves of solid explosive has a thickness below the xe2x80x9cdetonation failure thicknessxe2x80x9d of the explosive. The xe2x80x9cdetonation failure thicknessxe2x80x9d is defined as the thickness below which a sample of the explosive material is not capable of supporting detonation. In the compressed state, the compressible foam is compressed and the explosive leaves are sufficiently close to support detonation. In the uncompressed state the compressible foam is expanded and the explosive leaves are not sufficiently close to support detonation.
The invention is useful as reactive armor on an armored military vehicle. The invention provides for switching the reactive armor between an explosive state and a non-explosive state by compressing and uncompressing the stack.